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Lizard nourishes its young via a … placenta

In “Superfreak of Evolution: The Lizard With a Humanlike Placenta” (Discover, April 9, 2012), Ed Yong reports

Whereas virtually all cold-blooded reptiles supply embryos with nutrients from a large egg yolk, five-inch-long Trachylepis ivensi females ovulate small, yolk-poor eggs that implant in the uterus. As the fetus develops, its tissues become intimately entangled with the blood vessels of its mother, providing ready access to nutrients and oxygen in the mother’s blood. Sound familiar? “The fetal tissues actually invade the uterine ones, much like in humans,” Blackburn says. “It’s totally unexpected.”

It doesn’t sound like a very advanced placenta, but it is definitely the same idea.

We tend to think that placentas are “better” because they are more complex systems. Which raises the question, better for what? The reptiles’ numbers game (lay many eggs, maybe guard them but maybe not) clearly works.

The placental mammals’ system reduces the number of offspring possible and creates a (literally) heavy parenting load. But it works too. It may be essential for high intelligence, but most mammals are not in fact highly intelligent. Many are not as smart as clever birds.

One wonders if this is what happened: A common ancestor of reptiles and mammals used a system like ivensi’s, but the reptiles lost theirs (except for a few holdouts) and the mammals refined theirs ….

5 Responses to Lizard nourishes its young via a … placenta

To this YEC its not unexpected and these examples have come up before.
Its just a great presumption that reproductive tactics define and classify biological relationships.
In fact its no big deal or difference how to change ones reproductive tactics.
It happened all the time.
Mechanism is known but results are.

This lizard simply has this tactic because it needs it.
All creatures have what they need yet its unrelated to heritage.
One would not say this lizard is a special descendent of mammals just because of this detail!
Other details matter more!
Likewise the most case is about marsupials and placentals.
Exact copies of wolves, bears, lions, moles, mice, tapirs etc are in both “groups” .
Yet they classify them as related only to each other in the group and not to their exact replicas outside the group.
Reproductive details being the big point.

Its a classic error in presumptions.

This also explains why after the flood Australia was filled with marsupials and not others.
Simply the creatures who migrated there collectively adapted a faster reproductive system.
No more a big deal then this liard dude.
No such thing as convergent evolution.
no such as evolution .

There is certainly a distinctly numinous quality about Evolutionism. As a god, it is not at all required to abide by its own laws, and may freely surprise in just about any which way it likes. … Isn’t that right Olly? Scratches random-chance unit.

But it is a jealous god which demands the most rigorous compliance with its dictats by the ‘heathen’.